Bayonet-type lamp socket assembly



Sept. 13, 1966 H. R. MARTIN BAYONET-TYPE LAMP SOCKET ASSEMBLY Filed Nov. 26, 1965 VVEN7"O/ HERBERT 80) MARTIN BY l-l/S ATTORNEY United States Patent 3,273,106 BAYONET-TYPE LAMP SOCKET ASSEMBLY Herbert Roy Martin, Glen Waverley, Victoria, Australia, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Nov. 26, 1963, Ser. No. 326,271

Claims priority, application Australia, Apr. 19, 1963,

8 Claims. (Cl. 339-188) The present invention relates to automobile and other lamp socket assemblies of the type which include a substantially tubular housing which has open front and rear ends, a contact carrier member composed of electrically insulating material and receivable within the housing through its open front end so as to be slidably accommodated in the bore thereof, at least one terminal contact in said carrier member, at least one conductor Wire passing through the open rear end of the housing and connected to the terminal contact, compression spring means mounted within the housing so as to extend between abutment means thereon at or adjacent the rear end thereof and the carrier member, and lamp connecting means at or adjacent the front end of the housing, the arrangement being such that a lamp may be removably mounted in the front end of the housing so that each contact member on the lamp engages with the associated terminal contact on the carrier member under the action of the compression spring means.

Such lamp socket assemblies as those referred to may be used to form a component of a rear light assembly unit of an automobile and for this purpose the housing is generally provided with mounting means so that it can be readily snapped into an apertured support in a body panel of the automobile. If the lamp socket assembly is provided for a single lamp with a single filament, current from the automobile battery may be supplied through the conductor wire to the filament and returned through the metal of the body-panels of the automobile.

It will be appreciated that for this purpose a single conductor wire and a single contact preferably located axially in the contact carrier member is all that is required but if the lamp socket assembly is provided to accommodate a lamp with more than one filament, then a. plurality of conductor wires and terminal contacts will be required to associate with the filaments. With such a construction the housing would normally be constructed of metal but it should be understood that the invention is equally applicable to lamp socket assemblies wherein the housing is constructed of electrically non-conductive material. Obviously in such a case earthing means independent of the housing need to be provided.

Hitherto with lamp socket assemblies of the kind indicated, it has been found that when the socket assembly is removed from its support and the lamp is removed from the housing for replacement or service, the contact carrier member with its associated terminal contacts tend to emerge from the housing and in addition the terminal contacts tend to emerge from the carrier member. These tendencies arise from the resilience of the compression spring means and the inherent rigidity of the conductor wires. This can result in a short circuit due to the terminal contacts engaging with a metal body panel of the automobile with the possibility of fire occurring, possibly in a remote portion of the associated wiring system. This undesirable feature has been avoided in the past in some socket assemblies by locking the contact carrier member within the housing after the lamp socket assembly is produced by means of a separate manufacturing step in the form of a staking operation or by use of a tightfitting sleeve around the conductor wires and adjacent to the housing.

3,2731% Patented Sept. 13, 1966 However, the additional manufacturing step or part required to avoid this difliculty unnecessarily increases the cost of production of the resulting assembly.

The primary object of the present invention is to provide an improved lamp socket assembly of the kind indicated wherein the contact carrier member is normally retained in its operative position in the housing in a simple manner and yet may be readily removed if desired.

Accordingly the present invention provides a lamp socket assembly of the kind indicated wherein said contact carrier member incorporates rearwardly extending retaining means which in its operative position engages the rear end portion of said housing under the action of said compression spring means which acts to urge said contact carrier member towards the open front end of the housing, said retaining means being displaceable from its operative position to facilitate removal or installation of said contact carrier member from or in its operative position, the construction and arrangement of parts of the assembly being such that when the lamp is mounted in its operative position the contact carrier member is moved rearward bodily against the reaction of said compression spring means thus disengaging said retaining means from said rear end portion, whereas when the lamp is removed, the contact carrier member is moved forward bodily under the action of said compression spring means an axial distance positively limited by automatic re-engagemen-t of said retaining means with said rear end portion, thus preventing or minimizing the possibility of said contact carrier member being unintentionally ejected bodily through the open front end of the housing When the lamp is removed.

In order to more fully describe the invention reference is now made to the accompanying drawing in which:

FIGURE 1 is a sectional view of a lamp socket assembly on enlarged scale,

FIGURE 2 is a side View on different scale of the housing of the assembly shown in FIGURE 1,

FIGURE 3 is an end view of FIGURE 2 from the right hand side,

FIGURE 4 is a sectional view on different scale of the contact carrier member of the assembly shown in FIG- URE 1,

FIGURE 5 is an end view of FIGURE 4 from the right hand side,

FIGURE 6 is a sectional vie-w of a modified contact carrier member,

FIGURE 7 is an end view of FIGURE 6 from the right hand side.

An improved lamp socket assembly in accordance with the present invention includes a housing 8 which may be composed of metal and which is of substantially tubular open-ended formation. Preferably the housing is of substantially cylindrical formation throughout its length and is provided at or adjacent its rear end 9 with abutment means to engage with compression spring means 11 hereinafter described. The abutment means associated with the housing may be in the form of an annular flange 12 extending radially inwardly from the rear end .of the housing so as to bound a central aperture 1 3, FIG. 30.

The oposite or front end 14 of the housing is preferably provided with mounting means which may be in the form of a plurality of resilient fingers 16 carried by a mounting flange 17 and which are adapted to snap int-o an apertured body panel or the like (not shown). In addition the housing is also provided with lamp-connecting means 18 at or adjacent its front end preferably in such a form as to provide the usual bayonet type connection employed with lamps.

Associated with the foregoing is a contact carirer member 19 which is preferably composed of resilient, electrically insulating material such as a material selected from the nylon (polyamide) group. The contact carrier member has a main body portion 21 and is adapted to be slidably accommodated within the housing 8. The main body portion is preferably provided with abutment means 27 and 28 adapted to co-operate with the aforesaid compression spring means 11 which is held between the contact carrier member and the abutment means on the housing. The compression spring means -11 is preferably in the form of ahelical spring which engages against the annular flange 12 at the rear end of the housing and against the abutment means on the contact carrier member.

The main body portion of the contact carrier member is provided with at least one contact-receiving aperture 22 passing therethrough and preferably substantially parallel to the axis of the contact carrier member. If the assembly is designed for a single-filament lamp then a single contact-receiving aperture only may be required and if this is the case it is preferably provided axially within the main body portion as shown in FIGURES 4 and 5. On the other hand a plurality of contactreceiving apertures may be required and these are preferably provided symmetrically in the main body portion. For example, a main body portion with two contactreceiving apertures may have them located on a common diameter and equally spaced between the axis and the periphery of the main body portion as shown in FIG- URES 6 and 7.

If more than one contact receiving aperture is employed the housing is preferably providedwith a longitudinally extending locating groove 23 opening inwardly towards the axis of the housing and extending substantially parallel to the latter axis to the open front end of the housing. The main body portion of the contact carrier member is then provided with a locating lug 24 which is slidably accommodated within the locating groove thus orientating the contact carrier member and its pair or more of terminal contacts with the lamp-connecting means thereby ensuring engagement between terminal contacts 26 located in each aperture 22 and a central metal element on an insulating base of the lamp contact members (not shown) when the lamp is inserted axially against an end of contact 26 into its operative position.

The main body portion is preferably constructed so as to have a head portion 27 of larger outside diameter than the main body portion 21 so as to provide a sub stantially endless shoulder 28 which serves as the abutment means for the compression spring means. The contact receiving apertures pass through the head portion but preferably the main body portion is hollowed to provide an axial pocket behind the head portion which communicates with the contact receiving apertures.

Each contact-receiving aperture 22 may be provided with an access slot 29, FIG. 5, which extends sidewardly from its associated aperture through the head portion and the main body portion to an open mouth 31 for a purpose hereinafter described.

Each of the contact-receiving apertures is adapted to receive and retain a terminal contact 26 connected to a conductor wire 32 and for this purpose each aperture is preferably provided with a plurality of ridges 33 separated by associated grooves 34 which run substantially parallel to the axis of the contact carrier member. The size of the ridges is predetermined in relation to the outside diameter of its associated terminal contact so that when the terminal contact is forced into its aperture 22, a portion of each ridge is displaced sideward into its adjacent grooves thus holding each terminal contact in its associated aperture under complementary or mating fit conditions.

Each conductor wire may be threaded through its as sociated contact receiving aperture from the rear side of the main body portion and the terminal contact is then connected to the Wire in any suitable manner such as by crimping after which it is forced together with the wire back into its contact receiving aperture.

Alternatively the terminal contact 26 may be connected to its associated conductor wire 32 before the wire is assembled with the contact carrier member 19 after which the conductor wire may be pressed sidewardly into its associated aperture 22 through its open mouth 31 and access slot 29 connected therewith. Such a procedure facilitates mass production because the terminal contacts can be connected to the conductor wires independent of the lamp socket assembly and subsequently inserted into the contact carrier member in the manner described.

Associated with the aforesaid main body portion of the contact carrier member is yieldable retaining means which in accordance with the invention consist of a plurality of resilient legs 36 extending rearwardly from the main body portion and provided at their free ends with associated feet 37. Each leg is of predetermined length and its associated foot extends sidewardly away from the axis of the contact carrier member so as to provide a front face or ledge 38 at substantially right angles thereto and facing towards the main body portion. The opposite or rear face 39 of each foot is preferably tapered towards the axis of the contact carrier member and away from the main body portion so that when the contact carrier member is slidably inserted into the housing the tapered rear face of each leg engages the inner edge portion 41 of the annular flange which surrounds the central access aperture and rides over this edge portion so as to displace each foot inwardly towards the axis of the housing until the contact carrier member has been inserted a suflicient distance into the housing to enable the legs to snap outwardly away from the axis of the housing with the front face 38 of each foot located behind the annular flange 12.

The compression spring means 11 is held between the abutment means both of the carrier member and the housing and under the influence thereof the contact carrier member tends to be ejected from the housing but is prevented from doing so by engagement of the ledge of each foot with the rear side of the annular flange surrounding the central access aperture.

In use when a lamp (not shown) is inserted into the housing the contact carrier member is usually pressed some distance into the housing so that the feet are disengaged from the annular flange and therefore become inoperative. If however the lamp is removed the compression spring means forces the contact carrier member towards the open front end of the housing until the feet again engage the annular flange.

Thus when a lamp is removed from a socket assembly in accordance with this invention, the contact carrier member is restrained from being ejected from its housing and the possibility of a short circuit in this way is minimized or avoided, Furthermore it will be understood that the contact carrier member may be produced in a single moulding operation with the result that a separate manufactoring operation is not required to achieve this result.

Moreover the contact carrier member may be readily removed from the housing by first axially compressing the legs so as to allow the feet to clear the annular flange.

Having now described my invention, what I claim as new and desire to secure 'by Letters Patent is:

1. A lamp socket assembly, comprising a housing, a compression spring means within said housing, a contact carrier member which incorporates rearwardly extending retaining means specifically including at least a pair of axially diverging resilient legs having at their free ends outward feet each of which in its operative position engages the rear end portion of said housing under the action of said compression spring means which acts to urge said contact carrier member towards the open front end of the housing, said retaining means including said feet and legs being displaceable from its operative position into a clearance condition of said feet and legs free of engagement with said rear end portion to facilitate removal and installation of said contact carrier member from, as well as in its operative position, the construction and arrangement of parts of the assembly being such that when the lamp is mounted in its operative position the contact carrier member is moved rearward bodily against the reaction of said compression spring means thus disengaging said retaining means including both said feet and legs clearly spaced away from said rear end portion, whereas when the lamp is removed, the contact carrier member is moved forward bodily under the action of said compression spring means an axial distance positively limited by automatic re-engagement of said retaining means centralized axially by said legs again with said feet against said rear end portion, thus hindering the possibility of said contact carrier member being unintentionally ejected bodily through the open front end of the housing when the lamp is removed, said feet and legs both engaging said rear end portion during the condition of lamp removal.

2. A lamp socket assembly as claimed in claim 1 wherein said contact carrier member is composed of resilient material, said contact carrier member being slidably accommodated within the bore of said housing and having a main body portion from which said retaining means extends rearwardly, each leg being resiliently biased away from the axis and being together with its associated foot of such predetermined dimensions and relative configuration that only when the lamp is removed the feet cooperate and are operative to engage the rear side of the rear end portion of said housing at circumferentially spaced points, the legs being axially compressible to enable the feet to clear the rear end portion of the housing to facilitate the removal or installation of said contact carrier member.

3. A lamp socket assembly as claimed in claim 2 wherein the abutment means associated with the housing is in the form of an annular flange extending radially inwardly from the rear end of the housing and towards the axis thereof so as to bound a central aperture, the foot associated with each leg having a front face at substantially right angles to the axis of said contact carrier member facing the main body portion and an opposite rear face which is tapered towards the axis of and away from the main body portion of the contact carrier member, the construction and arrangement of the legs being such that as the contact carrier member is slidably inserted against the reaction of said compression spring means into the housing during installation the tapered rear faces of the legs engage the inner edge portion of the annular flange surrounding the access aperture causing the feet to be progressively compressed radially inwardly until the contact carrier member has been inserted a suflicient distance to enable the feet to snap radially outwardly behind said annular flange.

4. A lamp sock assembly as claimed in claim 3 wherein said compression spring means is a helical spring, the main body portion having a head portion on that side remote from the retaining means and of larger outside diameter than the main body portion thus forming an endless shoulder on the rear side of the head portion and surrounding the main body portion, said helical spring surrounding part of the retaining means including particularly said axially diverging resilient legs and being held under compression between the endless shoulder and the annular flange.

5. A lamp socket assembly as claimed in claim 4 wherein the head portion is provided with one contact'receiving aperture for each terminal contact and the main body portion is hollow so as to provide a rearwardly open axial pocket behand said head portion which directly communicates with each contact-receiving aperture per se, each said contact-receiving aperture being substantially parallel to the axis of the contact carrier member and being preformed with a plurality of ridges circumfer entially spaced by associated grooves which are substantially parallel to the last mentioned axis, the size of the ridges being predetermined in relation to the outside diameter of the associated terminal contact so that it is held in its contact receiving aperture under complementary and mating conditions.

6. A lamp socket assembly as claimed in claim 5 wherein each contact-receiving aperture is provided with one access slot which extends sidewardly from its associated aperture from the head portion and the associated main body portion to an open mouth through which the associated terminal contact conductor wire may be removed and installed.

7. A lamp socket assembly as claimed in claim 6 wherein said housing is constructed of metal and said contact carrier member has only one contact-receiving aperture which is axially located diametrically between said axially diverging resilient legs.

8. A lamp socket assembly as claimed in claim 6 wherein said contact carrier member has two contact-receiving apertures located symmetrically on a common diameter with the access slots correspondingly extending substantially radially with their open mouths being separated by substantially 180, said housing being provided with a longitudinally extending locating groove opening inwardly and extending substantially parallel to the axis of the housing and to the open front end thereof, the head portion being provided with a locating lug which is slidably accomodated within the locating groove thus orientating the contact carrier member and its associated pair of terminal contacts axially with the lamp connecting means, thereby ensuring engagement between the terminal contacts and the lamp contact members when the lamp is in its operative position.

References Cited by the Examiner UNITED STATES PATENTS 2,465,753 3/1949 Ross 339128 X 2,621,283 12/1952 Johnson 339128 X 2,904,772 9/1959 Ar-tz 339-17 X 2,913,791 11/1959 Martin 339 X 3,093,887 6/1963 Prestige et al. 339221 X 3,170,751 2/1965 Heller 339188 3,176,121 3/1965 Cook et al. 339-188 X FOREIGN PATENTS 999,232 7/1965 Great Britain.

EDWARD C. ALLEN, Primary Examiner.

ALFRED S. TRASK, Examiner, 

1. A LAMP SOCKET ASSEMBLY, COMPRISING A HOUSING, A COMPRESSION SPRING MEANS WITHIN SAID HOUSING, A CONTACT CARRIER MEMBER WHICH INCORPORATES REARWARDLY EXTENDING RETAINING MEANS SPECIFICALLY INCLUDING AT LEAST A PAIR OF AXIALLY DIVERGING RESILIENT LEGS HAVING AT THEIR FREE ENDS OUTWARD FEET EACH OF WHICH IN ITS OPERATIVE POSITION ENGAGES THE REAR END PORTION OF SAID HOUSING UNDER THE ACTION OF SAID COMPRESSION SPRING MEANS WHICH ACTS TO URGE SAID CONTACT CARRIER MEMBER TOWARDS THE OPEN FRONT END OF THE HOUSING, SAID RETAINING MEANS INCLUDING SAID FEET AND LEGS BEING DISPLACEABLE FROM ITS OPERATIVE POSITION INTO A CLEARANCE CONDITION OF SAID FEET AND LEGS FREE OF ENGAGEMENT WITH SAID REAR END PORTION TO FACILITATE REMOVAL AND INSTALLATION OF SAID CONTACT CARRIER MEMBER FROM, AS WELL AS IN ITS OPERATIVE POSITION, THE CONSTRUCTION AND ARRANGEMENT OF PARTS OF THE ASSEMBLY BEING SUCH THAT WHEN THE LAMP IS MOUNTED IN ITS OPERATIVE POSITION THE CONTACT CARRIER MEMBER IS MOVED REARWARD BODILY AGAINST THE REACTION OF SAID COMPRESSION SPRING MEANS THUS DISENGAGING SAID RETAINING MEANS INCLUDING BOTH SAID FEET AND LEGS CLEARLY SPACED AWAY FROM SAID REAR END PORTION, WHEREAS WHEN THE LAMP IS REMOVED, THE CONTACT CARRIER MEMBER IS MOVED FORWARD BODILY UNDER THE ACTION OF SAID COMPRESSION SPRING MEANS AN AXIAL DISTANCE POSITIVELY LIMITED BY AUTOMATIC RE-ENGAGEMENT OF SAID RETAINING MEANS CENTRALIZED AXIALLY BY SAID LEGS AGAIN WITH SAID FEET AGAINST SAID REAR END PORTION, THUS HINDERING THE POSSIBILITY OF SAID CONTACT CARRIER MEMBER BEING UNINTENTIONALLY EJECTED BODILY THROUGH THE OPEN FRONT END OF THE HOUSING WHEN THE LAMP IS REMOVED, SAID FEET AND LEGS BOTH ENGAGING SAID REAR END PORTION DURING THE CONDITION OF LAMP REMOVAL. 